Lithium Iron Oxide (LiFeO2) for Electroreduction of Dinitrogen to Ammonia

Microwave-Assisted Hydrothermal Synthesis of {100} and {111} Faceted LiFeO2 Truncated Octahedra: Investigations on Volatile Organic Compound Sensing Performance

Growth of exposed crystal facets has received considerable attention because of their coordinatively unsaturated surface atoms and defect-related surface reactivities. Herein, LiFeO2 truncated octahedra exposed with 6 {100} facets and 8 {111} facets were prepared through a simple microwave-assisted hydrothermal method without using any additives, surfactants, and calcination processes. The detailed growth process revealed that the formation of LiFeO2 truncated octahedra occurred only at the optimized reaction temperature (180 °C), time (30 min), and reactant concentrations. The prepared LiFeO2 truncated octahedra showed excellent sensing responses toward aliphatic organic compounds compared to that against aromatic organic compounds and poor response to inorganic compounds. The response percentages of 150 ppm concentrations of acetone, ethanol, formaldehyde, and isopropyl alcohol are 81.84, 62.91, 62.68, and 69.41%, respectively, at a low operating temperature (100 °C). The presence of exposed facets with their coordinatively unsaturated Li/Fe surface atoms such as 5-fold {100}, 3-fold {111}, 3-fold {100}-{111}, 2-fold {111}-{111}, and 2-fold coordination with the O atom in the vertices facilitated more oxygen vacancies and led to improved surface reactivities as well as sensitivity.

Mineral Phase Reconfiguration Enables the High Enzyme-like Activity of Vermiculite for Antibacterial Application

Phyllosilicates-based nanomaterials, particularly iron-rich vermiculite (VMT), have wide applications in biomedicine. However, the lack of effective methods to activate the functional layer covered by the external inert layer limits their future applications. Herein, we report a mineral phase reconfiguration strategy to prepare novel nanozymes by a molten salt method. The peroxidase-like activity of the VMT reconfiguration nanozyme is 10 times that of VMT, due to the electronic structure change of iron in VMT. Density-functional theory calculations confirmed that the upward shifted d-band center of the VMT reconfiguration nanozyme promoted the adsorption of H2O2 on the active iron sites and significantly elongated the O-O bond lengths. The reconfiguration nanozyme exhibited nearly 100% antibacterial activity toward Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), much higher than that of VMT (E. coli 10%, S. aureus 21%). This work provides new insights for the rational design of efficient bioactive phyllosilicates-based nanozyme.

Promoting Nitrite-to-Ammonia Electroreduction over Amorphous CoS2 Nanorods

Electrocatalytic nitrite reduction to ammonia (NO2RR) emerges as a promising route to simultaneously attain harmful NO2- removal and green NH3 synthesis. In this study, amorphous CoS2 nanorods (a-CoS2) are first demonstrated as an effective NO2RR catalyst, which exhibits the maximum FENH3 of 88.7% and NH3 yield rate of 438.1 μmol h-1 cm-2 at -0.6 V vs RHE. Detailed experimental and computational investigations reveal that the high NO2RR performance of a-CoS2 originates from the amorphization-induced S vacancies to facilitate NO2- activation and hydrogenation, boost the electron transport kinetics, and inhibit the competitive hydrogen evolution.

Ti-doped iron phosphide nanoarrays grown on carbon cloth as a self-supported electrode for enhanced electrocatalytic nitrogen reduction

The electrocatalytic nitrogen reduction reaction (eNRR) has been widely recognized as a promising method for green ammonia synthesis. However, the inert NN bond, inferior catalytic activity and small electrochemically active area impede its practical application. To circumvent these problems, we proposed self-supported Ti-doped iron phosphide (FeP) nanorod arrays grown on carbon cloth (Ti-FeP/CC) as an electrode for eNRR. The introduction of Ti doping sites regulated the electron structure of FeP, leading to electron migration from Fe to P, which facilitated N2-to-NH3 conversion. The as-prepared Ti-FeP/CC showed an enhancement of electrochemical surface area (ECSA), high electrical conductivity and well-exposed active sites. Ti-FeP/CC was capable of producing a high NH3 yield of 10.93 μg h-1 cm-2 and faradaic efficiency of 10.77% at an optimal voltage of -0.3 V (vs. RHE) in a 0.1 M Na2SO4 solution with excellent stability and durability during the eNRR process. This work not only presents a promising electrode material for eNRR, but also provides a new insight into rational heteroatom doping for electrocatalysis.

Catalysis of dinitrogen activation and reduction by a single Fe13 cluster and its doped systems

Catalyzing N₂ reduction to ammonia under ambient conditions is known to be significant both in the fertilizer industry and life sciences. To unveil the synergy of multiple sites, here, we have studied the catalysis of ammonia synthesis using a typical Fe₁₃ cluster and its doped systems, Fe₁₂X (X = V, Cr, Mn, Co, Ni, Cu, Zn, Nb, Mo, Ru, and Rh). The energetics analysis showed that center substitution (X@Fe₁₂) was favored while doping single V, Cr, Co, and Mo atoms, whereas Mn, Ni, Cu, Zn, Nb, Ru, and Rh tended to form shell-doped structures (Fe₁₂X). Among all the 13 clusters, Fe₁₂Nb exhibited the lowest activation energy for N₂ dissociation; moreover, in the hydrogenation process, Fe₁₂Nb could convert N₂ to ammonia efficiently. We have fully illustrated the reaction dynamics and structural chemistry essence of these diverse 13-atom systems and propose Fe₁₂Nb as an ideal candidate for catalytic ammonia synthesis.

In Situ Derived Co2B Nanosheet Array: A High-Efficiency Electrocatalyst for Ambient Ammonia Synthesis via Nitrate Reduction

Ambient ammonia synthesis via electrochemical nitrate (NO3-) reduction is regarded as a green alternative to the Haber-Bosch process. Herein, we report the in situ derivation of an amorphous Co2B layer on a Co3O4 nanosheet array on a Ti mesh (Co2B@Co3O4/TM) for efficient NH3 production via selective electroreduction of NO3- under ambient conditions. In 0.1 M PBS and 0.1 M NaNO3, Co2B@Co3O4/TM exhibits a maximum Faradaic efficiency of 97.0% at -0.70 V and a remarkable NH3 yield of 8.57 mg/h/cm2 at -1.0 V, with durability for stable NO3--to-NH3 conversion over eight recycling tests and 12 h of electrolysis. Additionally, it can be applied as an efficient cathode material for Zn-NO3- batteries to produce NH3 while generating electricity. The catalytic mechanisms on Co2B@Co3O4 are further revealed by theoretical calculations.

PdFe Single-Atom Alloy Metallene for N2 Electroreduction

Single-atom alloys hold great promise for electrocatalytic nitrogen reduction reaction (NRR), while the comprehensive experimental/theoretical investigations of SAAs for the NRR are still missing. Herein, PdFe₁ single-atom alloy metallene, in which the Fe single atoms are confined on a Pd metallene support, is first developed as an effective and robust NRR electrocatalyst, delivering exceptional NRR performance with an NH₃ yield of 111.9 μg h^-1  mg^-1 , a Faradaic efficiency of 37.8 % at -0.2 V (RHE), as well as a long-term stability for 100 h electrolysis. In-depth mechanistic investigations by theoretical computations and operando X-ray absorption/Raman spectroscopy indentify Pd-coordinated Fe single atoms as active centers to enable efficient N₂ activation via N₂ -to-Fe σ-donation, reduced protonation energy barriers, suppressed hydrogen evolution and excellent thermodynamic stability, thus accounting for the high activity, selectivity and stability of PdFe₁ for the NRR.

Photoreduction of carbon dioxide and photodegradation of organic pollutants using alkali cobalt oxides MCoO2 (M = Li or Na) as catalysts

The recycling of lithium batteries should be prioritized, and the use of discarded alkali metal battery electrode materials as photocatalysts merits research attention. This study synthesized alkali metal cobalt oxide (MCoO₂, M = Li or Na) as a photocatalyst for the photoreduction of CO₂ and degradation of toxic organic substances. The optimized NaCoO₂ and LiCoO₂ photocatalysts increased the photocatalytic CO₂-CH₄ conversion rate to 21.0 and 13.4 μmol g^-1 h^-1 under ultraviolet light irradiation and to 16.2 and 5.3 μmol g^-1 h^-1 under visible light irradiation, which is 17 times higher than that achieved by TiO₂ P25. The rate constants of the optimized reactions of crystal violet (CV) with LiCoO₂ and NaCoO₂ were 2.29 × 10^-2 and 4.35 × 10^-2 h^-1, respectively. The quenching effect of the scavengers and electron paramagnetic resonance in CV degradation indicated that active O₂^•-, ¹O₂, and h⁺ play the main role, whereas ^•OH plays a minor role for LiCoO₂. The hyperfine splitting of the DMPO-^•OH and DMPO-^•CH₃ adducts was a_N = 1.508 mT, a_Hβ = 1.478 mT and a_N = 1.558 mT, a_Hβ = 2.267 mT, respectively, whereas the hyperfine splitting of DMPO^+• was a_N = 1.475 mT. The quenching effect also indicated that active O₂^•- and h⁺ play the main role and that ^•OH and ¹O₂ play a minor role for NaCoO₂. The hyperfine splitting of the DMPO-^•OH and DMPO^+• adducts was a_N = 1.517 mT, a_Hβ = 1.489 mT and a_N = 1.496 mT, respectively. Discarded alkali metal battery electrode materials can be reused as photocatalysts to address environmental pollution.

Relative Kinetics of Solid-State Reactions: The Role of Architecture in Controlling Reactivity

Countless inorganic materials are prepared via high temperature solid-state reaction of mixtures of reagents powders. Understanding and controlling the phenomena that limit these solid-state reactions is crucial to designing reactions for new materials synthesis. Here, focusing on topotactic ion-exchange between NaFeO₂ and LiBr as a model reaction, we manipulate the mesoscale reaction architecture and transport pathways by changing the packing and interfacial contact between reagent particles. Through analysis of in situ synchrotron X-ray diffraction data, we identify multiple kinetic regimes that reflect transport limitations on different length scales: a fast kinetic regime in the first minutes of the reaction and a slow kinetic regime that follows. The fast kinetic regime dominates the observed reaction progress and depends on the reagent packing; this challenges the view that solid-state reactions are necessarily slow. Using a phase-field model, we simulated the reaction process and showed that particles without direct contact to the other reactant phases experience large reduction in the reaction rate, even when transport hindrance at particle-particle contacts is not considered.

A vacancy engineered MnO2-x electrocatalyst promotes nitrate electroreduction to ammonia

The NO₃^- reduction reaction (NO₃RR) has recently emerged as a potential approach for sustainable and efficient NH₃ production, whereas exploring high-performance NO₃RR electrocatalysts is highly desirable yet challenging. Herein, we attempted to construct O-vacancies (OVs) on MnO₂ nanosheets and the resulting OV-rich MnO_2-x showed a high NH₃ yield of 3.34 mg h^-1 cm^-2 (at -1.0 V vs. RHE) and an excellent FE of 92.4% (at -0.9 V vs. RHE), together with the outstanding stability. DFT calculations reveal that OVs on MnO₂ serve as catalytic centers to enhance NO₃^- adsorption and dissociation, reduce the energy barriers of hydrogenation steps and thus promote NO₃^--to-NH₃ conversion.

Boosted nitrate electroreduction to ammonia on Fe-doped SnS2 nanosheet arrays rich in S-vacancies

The electrochemical nitrate reduction reaction (NO₃RR) not only holds great potential for the removal of NO₃^- contaminants from the environment, but also potentially provides a renewable-energy-driven NH₃ synthesis method to replace the Haber-Bosch process. Herein, we report that Fe-doped SnS₂ nanosheets enriched with S-vacancies can be used as an efficient NO₃RR catalyst, showing a high NH₃ yield of 7.2 mg h^-1 cm^-2 (at -0.8 V) and a faradaic efficiency of 85.6% (at -0.7 V). Density functional theory (DFT) calculations revealed that S-vacancies on Fe-SnS₂ serve as the main active sites for the NO₃RR and the Fe-doping can further regulate the electronic structure of S-vacancies to optimize the binding energies of NO₃RR intermediates, resulting in reduced energy barriers and enhanced NO₃RR activity.

High-Efficiency N2 Electroreduction Enabled by Se-Vacancy-Rich WSe2-x in Water-in-Salt Electrolytes

Electrocatalytic nitrogen reduction reaction (NRR) is a promising approach for renewable NH₃ production, while developing the NRR electrocatalysis systems with both high activity and selectivity remains a significant challenge. Herein, we combine catalyst and electrolyte engineering to achieve a high-efficiency NRR enabled by a Se-vacancy-rich WSe_2-x catalyst in water-in-salt electrolyte (WISE). Extensive characterizations, theoretical calculations, and in situ X-ray photoelectron/Raman spectroscopy reveal that WISE ensures suppressed H₂ evolution, improved N₂ affinity on the catalyst surface, as well as an enhanced π-back-donation ability of active sites, thereby promoting both activity and selectivity for the NRR. As a result, an excellent faradaic efficiency of 62.5% and NH₃ yield of 181.3 μg h^-1 mg^-1 is achieved with WSe_2-x in 12 m LiClO₄, which is among the highest NRR performances reported to date.

Chloride-Derived Bimetallic Cu-Fe Nanoparticles for High-Selective Nitrate-to-Ammonia Electrochemical Catalysis

Cu-based bimetallic materials have been widely reported as efficient catalysts for electrocatalytic nitrate reduction. However, the faradaic efficiency and selectivity are still far from satisfactory. Herein, Cu-Fe bimetallic nanoalloys with adjustable Cu/Fe ratios are successfully prepared through a reactive mechanical milling approach with CuCl2, FeCl3 and Na as the starting materials. The optimized Cu3Fe exhibits excellent nitrate conversion efficiency of 81.1% and 70.3% ammonia selectivity at −0.7 V vs. RHE within 6 h under 0.1 M Na2SO4 and 100 ppm NO3−. The Fe-introduction-induced upshift of the d-band center is identified to be beneficial for promoting nitrate adsorption on Cu3Fe. Moreover, favorable H generation under the assistance of Fe could effectively accelerate the stepwise hydrogenation during electrocatalytic nitrate reduction, resulting in significantly improved NH4+ selectivity. This work supplies valuable insights for the rational design of transition-metal-based bimetallic catalysts for electrocatalytic nitrate reduction.

MXene quantum dots decorated Ni nanoflowers for efficient Cr (VI) reduction

Nickel@MXene quantum dots (Ni@MQDs), as novel flower-like hybrid materials, were firstly prepared through a simple reduction method. The Ni@MQDs exhibited an outstanding catalytic performance for Cr (VI) reduction with a low activation energy (E_a = 18.9 kJ mol^-1) and a high kinetic constant (k = 0.4779 min^-1) in the presence of formic acid (HCOOH). Density functional theory calculations demonstrated that Ni@MQDs exhibited an upshift of d-band center of active Ni atoms to promote the adsorption of both HCOOH and active H atoms, as well as an improved conductivity to boost the catalytic reaction kinetics, leading to the most favorable catalytic performance. This work may open up a new avenue towards the design and synthesis of novel MQDs-based hybrid catalysts for wastewater treatment.

Metal-free BN quantum dots/graphitic C3N4 heterostructure for nitrogen reduction reaction

Exploring high-efficiency metal-free electrocatalysts towards N₂ reduction reaction (NRR) is of great interest for the development of electrocatalytic N₂ fixation technology. Herein, we combined boron nitride quantum dots (BNQDs) and graphitic carbon nitride (C₃N₄) to design a metal-free BNQDs/C₃N₄ heterostructure as an effective and durable NRR catalyst. The electronically coupled BNQDs/C₃N₄ presented an NH₃ yield as high as 72.3 μg h^-1 mg^-1 (-0.3 V) and a Faradaic efficiency of 19.5% (-0.2 V), far superior to isolated BNQDs and C₃N₄, and outperforming nearly all previously reported metal-free catalysts. Theoretical computations unveiled that the N₂ activation could be drastically enhanced at the BNQDs-C₃N₄ interface where interfacial BNQDs and C₃N₄ cooperatively adsorb N₂ and stabilize *N₂H intermediate, leading to the significantly promoted NRR process with an ultra-low overpotential of 0.23 V.

Regulating Pd nanosheets by W-doping for electrochemical nitrate reduction to ammonia

PdW nanosheets exhibit a high NO3RR activity, attributed to the W-alloying-induced upshift of the d-band center of Pd to enhance the NO3− activation and reduce the energy barriers of the NO3RR process.

Ultrasmall iridium nanoparticles on graphene for efficient nitrogen reduction reaction

Ultrasmall iridium nanoparticles on reduced graphene oxide (Ir/RGO) exhibited a high NRR activity, attributed to the RGO-induced upshifting of the d-band center for active Ir sites, leading to decreased NRR energy barriers.

Boosting electrochemical nitrogen reduction to ammonia with high efficiency using a LiNb3O8 electrocatalyst in neutral media

The nitrogen reduction reaction (NRR) has great potential as a method to replace the industrial Haber-Bosch process for ammonia synthesis. Nevertheless, the efficiency of the NRR is mainly dependent on the rational design of highly efficient and active electrocatalysts on account of the high energy of N₂ and HER as a competitive reaction. Herein, a simple solid-phase synthesis method is adopted to design and synthesize a LiNb₃O₈ (LNO) electrocatalyst, which proves that the synergistic effect of electron-rich Nb and Li elements can effectively improve the NRR activity of commercial Nb₂O₅ and Li₂CO₃. The resultant LNO electrocatalyst presents an ammonia yield rate of 7.85 μg h^-1 mg_cat.^-1 with a faradaic efficiency of 82.83% at -0.4 V vs. RHE under ambient conditions, which are much higher than those of commercial Nb₂O₅ (1.67 μg h^-1 mg_cat.^-1, 13.51%) and Li₂CO₃ (1.93 μg h^-1 mg_cat.^-1, 8.41%). Detailed characterizations demonstrate that the obtained LNO electrocatalyst has a larger specific surface area of electrochemical activity and more active sites to promote the activity of the NRR. Moreover, the synergistic effect of Li and Nb elements greatly improves the hydrophobicity of the material, which is more conducive to the occurrence of the NRR. This work highlights the enormous potential of the LNO electrocatalyst with a hydrophobic surface and easy activation of NN for highly efficient ammonia synthesis under ambient conditions.

Spin-dependent Optical Excitations in LiFeO2

The three-dimensional ternary LiFeO₂ compound presents various unusual properties. The main features are thoroughly explored by using many-body perturbation theory. The concise physical/chemical picture, the critical spin polarizations, and orbital hybridizations in the Li-O and Fe-O bonds are clearly examined through geometric optimization, quasi-particle energy spectra, spin-polarized density of states, spatial charge densities, spin-density distributions, and strong optical responses. The unusual optical transitions cover various frequency-dependent absorption structures, and the most prominent plasmon modes are identified from the dielectric functions, energy loss functions, reflectance spectra, and absorption coefficients. Optical excitations are anisotropic and strongly affected by excitonic effects. The close combinations of electronic, magnetic, and optical properties allow us to identify the significant spin polarizations and orbital hybridizations for each available excitation channel. The lithium ferrite compound can be used for spintronic and photo-catalysis applications.

Synergistic Enhancement of Electrocatalytic Nitrogen Reduction Over Boron Nitride Quantum Dots Decorated Nb2 CTx -MXene

Electrochemical N₂ fixation represents a promising strategy toward sustainable NH₃ synthesis, whereas the rational design of high-performance catalysts for the nitrogen reduction reaction (NRR) is urgently required but remains challenging. Herein, a novel hexagonal BN quantum dots (BNQDs) decorated Nb₂ CT_x -MXene (BNQDs@Nb₂ CT_x ) is explored as an efficient NRR catalyst. BNQDs@Nb₂ CT_x presents the optimum NRR activity with an NH₃ yield rate of 66.3 µg h^-1 mg^-1 (-0.4 V) and a Faradaic efficiency of 16.7% (-0.3 V), outperforming most of the state-of-the-art NRR catalysts, together with an excellent stability. Theoretical calculations revealed that the synergistic interplay of BNQDs and Nb₂ CT_x enabled the creation of unique interfacial B sites serving as NRR catalytic centers capable of enhancing the N₂ activation, lowering the reaction energy barrier and impeding the H₂ evolution.

MoS2 quantum dots for electrocatalytic N2 reduction

We demonstrate that MoS₂ quantum dots (QDs) can be an effective and durable catalyst for the electrocatalytic N₂ reduction reaction (NRR), showing an NH₃ yield of 39.6 μg h^-1 mg^-1 with a faradaic efficiency of 12.9% at -0.3 V, far superior to MoS₂ nanosheets and outperforming most reported NRR catalysts. Density functional theory computations unravel that the MoS₂ QDs can dramatically facilitate N₂ adsorption and activation via side-on patterns, resulting in an energetically-favored enzymatic pathway with an ultra-low overpotential of 0.29 V.

Defect Regulating of Few-Layer Antimonene from Acid-Assisted Exfoliation for Enhanced Electrocatalytic Nitrogen Fixation

Nitrogen reduction reaction (NRR), as a green and sustainable technology, is far from a practical application due to the lack of efficient electrocatalysts. In this work, we found that antimonene, a group-VA elemental two-dimensional (2D) material, is attractive as an electrocatalyst for NRR. The antimonene here is acquired through chemical exfoliation of antimony (Sb) using H₂SO₄ for the first time, which simultaneously achieved efficient large-sized exfoliation and created a high density of active edge sites. Moreover, the concentration of defects shows a gradual increasing tendency as the treatment time extends. The obtained antimonene exhibited favorable average ammonia (NH₃) yield and Faradaic efficiency as high as 2.08 μg h^-1 cm^-2 and 14.25% at -0.7 V versus RHE, respectively. Density functional theory calculations prove that the sufficient exposure of edge defects is favorable for reducing the reaction barrier and strengthening the interaction between antimonene and the intermediates of NRR, thus increasing the selectivity and yield rate of NH₃. The chemical exfoliation of Sb reported here offers an alternative avenue to engineer the surface structures of group-VA elemental-based catalysts. Investigation of NRR using 2D antimonene can further provide deep insight into the mechanism and principle of NRR over group-VA elemental nanosheets.

Metasequoia-like Nanocrystal of Iron-Doped Copper for Efficient Electrocatalytic Nitrate Reduction into Ammonia in Neutral Media

It is of significance to design catalysts for achieving high-performance electrochemical nitrate reduction to ammonia (NRA) in mild neutral media. However, the faradaic efficiency and selectivity are still far from satisfactory. Here, the fabrication of an efficient catalyst was achieved by rationally doping Fe to Cu into a metasequoia-like nanocrystal of CuFe for NRA in neutral media. Fe doping was found to deepen energy level of the Cu 3d band, favorably tuning adsorption energies of reaction intermediates to promote the NRA. At an applied potential of -0.7 V vs. the reversible hydrogen electrode, the CuFe with approximately 2 % Fe doping content delivered a catalytic current density of 55.6 mA cm^-2 , which was 2.1 times that of the Cu material. The CuFe also exhibited a faradaic efficiency up to 94.5 %, and a good selectivity of 86.8 %.

Electrochemical N2 fixation to NH3 under ambient conditions: porous LiFe5O8 nanoparticle–reduced graphene oxide as a highly efficient and selective catalyst

In this work, porous LiFe₅O₈–rGO achieves a high NH₃ yield of 36.025 mg h⁻¹ mg_cat.⁻¹ and a high faradaic efficiency of 13.08% at −0.2 V vs. the reversible hydrogen electrode in 0.1 M HCl.

A CeP nanoparticle-reduced graphene oxide hybrid: an efficient electrocatalyst for the NH3 synthesis under ambient conditions

In 0.1 M HCl, CeP–rGO achieves a large NH₃ yield of 28.69 μg h⁻¹ mg_cat.⁻¹ and a high faradaic efficiency of 9.6% at −0.40 V, and it also shows good stability. DFT calculations show that CeP–rGO can efficiently catalyze the synthesis of NH₃.

A spinel ferrite catalyst for efficient electroreduction of dinitrogen to ammonia

Ambient electrocatalytic N2 reduction reaction (NRR) provides an eco-friendly way for artificial NH3 production, while an efficient NRR process requires active and stable electrocatalysts. In this communication, we exploit the spinel ferrite NiFe2O4 as a promising NRR catalyst. The developed NiFe2O4 nanocubes/reduced graphene oxide (NiFe2O4/RGO) exhibited an appealing NRR performance with an NH3 yield of 32.2 μg h-1 mg-1 and a faradaic efficiency (FE) of 9.8% at -0.5 V (RHE), as well as a high catalytic durability. Mechanistic investigations revealed that the surface Fe atoms serve as key NRR active sites for favorable N2 adsorption and H+ suppression. These findings may facilitate the understanding and exploration of Earth-abundant spinel ferrite catalysts for electrochemical dinitrogen fixation.

ZrB2 as an earth-abundant metal diboride catalyst for electroreduction of dinitrogen to ammonia

ZrB₂ nanocubes show a high NH₃ production rate (37.7 μg h⁻¹ mg⁻¹) and Faradaic efficiency (18.2%), attributed to a unique tetranuclear N₂ adsorption side-on mode for ZrB₂ that could strongly activate N₂ and lower the reaction energy barrier.